Sporulation of Verticillium agaricinum and Schizosaccharomyces pombe in batch and chemostat culture

Abstract

A study was made of the effect of specific growth rate on sporulation of Verticillium agaricinum in batch culture and on sporulation of V. agaricinum and Schizosaccharomyces pombe in glucose-limited, chemostat culture; the specific growth rate of V. agaricinum was varied in batch culture by changing the carbon source in the medium. In each culture system, sporulation varied inversely with specific growth rate. Reduction in dilution rate of chemostat cultures of V. agaricinum and S. pombe was followed after ca 5 h and 4 h respectively by increased sporulation. Average times required for the formation of a free conidium from a vegetative hypha of V. agaricinum and an ascus from vegetative cells of S. pombe were ca 17 h and ca 10 h respectively. The results obtained were consistent with the hypothesis that sporulation is a probabilistic event, i.e. a vegetative cell has a fixed probability of undergoing sporulation. At high dilution rates ethanol and residual glucose accumulated in glucose-limited cultures of S. pombe and the presence of ethanol was correlated with a decrease in yield coefficient and a reduction in sporulation.